#!/usr/bin/env bash
set -euo pipefail
IFS=$'\n\t'

# Script Name:  docker-image-manager.v1.sh
# Beschreibung: Docker Image Manager - verwaltet und inspiziert Docker Images
#               - Alle Images auflisten
#               - Ungenutzte Images anzeigen
#               - Zeigt zugeordnete Container pro Image
#               - Images interaktiv loeschen
# Autor:        Patrick Asmus
# Web:          https://www.cleveradmin.de
# Git-Reposit.: https://git.techniverse.net/scriptos/docker-image-manager
# Version:      1.0.0
# Datum:        18.02.2026
# Modifikation: Initialer Release (v1.0.0)
#####################################################

LAST_IDS=()
LAST_LABELS=()
declare -A IMAGE_TO_CONTAINERS=()
SELECTED_IDS=()
SELECTED_LABELS=()

require_docker() {
  if ! command -v docker >/dev/null 2>&1; then
    echo "Docker CLI nicht gefunden. Bitte Docker installieren und PATH pruefen." >&2
    exit 1
  fi

  if ! docker info >/dev/null 2>&1; then
    echo "Docker Daemon nicht erreichbar. Bitte Docker starten." >&2
    exit 1
  fi
}

load_container_map() {
  IMAGE_TO_CONTAINERS=()

  local -a lines
  mapfile -t lines < <(docker ps -a -q | xargs -r docker inspect --format '{{.Id}}|{{.Image}}|{{.Name}}')

  if [[ ${#lines[@]} -eq 0 ]]; then
    return 0
  fi

  local line image_id name
  for line in "${lines[@]}"; do
    IFS='|' read -r _ image_id name <<< "$line"
    name=${name#/}
    if [[ -n "${IMAGE_TO_CONTAINERS[$image_id]:-}" ]]; then
      IMAGE_TO_CONTAINERS[$image_id]="${IMAGE_TO_CONTAINERS[$image_id]},${name}"
    else
      IMAGE_TO_CONTAINERS[$image_id]="$name"
    fi
  done
}

print_images_table() {
  if [[ ${#LAST_IDS[@]} -eq 0 ]]; then
    echo "Keine Images gefunden."
    return 0
  fi

  load_container_map

  printf "%-4s %-30s %-20s %-15s %-12s %-20s %-30s\n" "Nr." "REPOSITORY" "TAG" "IMAGE ID" "SIZE" "CREATED" "CONTAINERS"
  printf "%-4s %-30s %-20s %-15s %-12s %-20s %-30s\n" "----" "------------------------------" "--------------------" "---------------" "------------" "--------------------" "------------------------------"

  for i in "${!LAST_IDS[@]}"; do
    IFS='|' read -r repo tag short_id size created <<< "${LAST_LABELS[$i]}"
    local containers="${IMAGE_TO_CONTAINERS[${LAST_IDS[$i]}]:-}"
    if [[ -z "$containers" ]]; then
      containers="-"
    fi
    printf "%-4s %-30s %-20s %-15s %-12s %-20s %-30s\n" "$((i + 1))" "$repo" "$tag" "$short_id" "$size" "$created" "$containers"
  done
}

load_images_from_lines() {
  local -a lines=("$@")
  LAST_IDS=()
  LAST_LABELS=()

  if [[ ${#lines[@]} -eq 0 ]]; then
    return 0
  fi

  local line id repo tag created size short_id
  for line in "${lines[@]}"; do
    IFS='|' read -r id repo tag created size <<< "$line"
    short_id=${id:0:12}
    LAST_IDS+=("$id")
    LAST_LABELS+=("$repo|$tag|$short_id|$size|$created")
  done
}

list_all_images() {
  local -a lines
  mapfile -t lines < <(docker images --no-trunc --format '{{.ID}}|{{.Repository}}|{{.Tag}}|{{.CreatedSince}}|{{.Size}}')
  load_images_from_lines "${lines[@]}"
  print_images_table
}

list_unused_images() {
  local used_file
  used_file=$(mktemp)

  if docker ps -a -q >/dev/null 2>&1; then
    docker ps -a -q | xargs -r docker inspect --format '{{.Image}}' | sort -u > "$used_file"
  fi

  local -a lines
  mapfile -t lines < <(docker images --no-trunc --format '{{.ID}}|{{.Repository}}|{{.Tag}}|{{.CreatedSince}}|{{.Size}}')

  LAST_IDS=()
  LAST_LABELS=()

  local line id repo tag created size short_id
  for line in "${lines[@]}"; do
    IFS='|' read -r id repo tag created size <<< "$line"
    if [[ ! -s "$used_file" ]] || ! grep -Fxq "$id" "$used_file"; then
      short_id=${id:0:12}
      LAST_IDS+=("$id")
      LAST_LABELS+=("$repo|$tag|$short_id|$size|$created")
    fi
  done

  rm -f "$used_file"
  print_images_table
}

confirm_action() {
  local prompt="$1"
  local answer
  read -r -e -p "$prompt [y/N]: " answer
  case "$answer" in
    y|Y|yes|YES) return 0 ;;
    *) return 1 ;;
  esac
}

select_images_by_numbers() {
  local -a numbers=()
  local input="${1:-}"

  SELECTED_IDS=()
  SELECTED_LABELS=()

  if [[ -z "$input" ]]; then
    read -r -e -p "Nummern der Images (z.B. 1,3,5) oder Enter fuer Abbruch: " input
  fi

  if [[ -z "$input" ]]; then
    echo "Abgebrochen."
    return 1
  fi

  input=${input//,/ }
  for token in $input; do
    if [[ "$token" =~ ^[0-9]+$ ]]; then
      numbers+=("$token")
    fi
  done

  if [[ ${#numbers[@]} -eq 0 ]]; then
    echo "Keine gueltigen Nummern angegeben."
    return 1
  fi

  local idx
  for idx in "${numbers[@]}"; do
    if (( idx < 1 || idx > ${#LAST_IDS[@]} )); then
      echo "Nummer $idx ist ungueltig."
      return 1
    fi
    SELECTED_IDS+=("${LAST_IDS[$((idx - 1))]}")
    SELECTED_LABELS+=("${LAST_LABELS[$((idx - 1))]}")
  done

  return 0
}

print_selected_images() {
  if [[ ${#SELECTED_IDS[@]} -eq 0 ]]; then
    return 0
  fi

  printf "%-4s %-30s %-20s %-15s %-12s %-20s\n" "Nr." "REPOSITORY" "TAG" "IMAGE ID" "SIZE" "CREATED"
  printf "%-4s %-30s %-20s %-15s %-12s %-20s\n" "----" "------------------------------" "--------------------" "---------------" "------------" "--------------------"

  local i
  for i in "${!SELECTED_IDS[@]}"; do
    IFS='|' read -r repo tag short_id size created <<< "${SELECTED_LABELS[$i]}"
    printf "%-4s %-30s %-20s %-15s %-12s %-20s\n" "$((i + 1))" "$repo" "$tag" "$short_id" "$size" "$created"
  done
}

remove_image_by_id() {
  local id="$1"
  local -a used
  mapfile -t used < <(docker ps -a --filter "ancestor=$id" --format '{{.ID}}|{{.Names}}')
  if [[ ${#used[@]} -gt 0 ]]; then
    echo "Ueberspringe Image (in Benutzung durch Container): $id"
    local entry
    for entry in "${used[@]}"; do
      echo "- ${entry#*|} (${entry%%|*})"
    done
    return
  fi

  local -a tags=()
  mapfile -t tags < <(docker image inspect "$id" --format '{{range .RepoTags}}{{println .}}{{end}}')

  if [[ ${#tags[@]} -eq 0 ]]; then
    echo "Loesche Image: $id"
    docker rmi "$id"
    return
  fi

  local tag
  local -a tag_list=()
  for tag in "${tags[@]}"; do
    if [[ "$tag" == "<none>:<none>" || -z "$tag" ]]; then
      continue
    fi
    tag_list+=("$tag")
  done

  if [[ ${#tag_list[@]} -eq 0 ]]; then
    echo "Loesche Image: $id"
    docker rmi "$id"
    return
  fi

  for tag in "${tag_list[@]}"; do
    echo "Loesche Tag: $tag"
    docker rmi "$tag"
  done

  if docker image inspect "$id" >/dev/null 2>&1; then
    echo "Loesche Image: $id"
    docker rmi "$id"
  fi
}

delete_selected_images() {
  local -A seen=()
  local id
  for id in "${SELECTED_IDS[@]}"; do
    if [[ -n "${seen[$id]:-}" ]]; then
      continue
    fi
    seen[$id]=1
    remove_image_by_id "$id"
  done
}

inspect_image_by_number() {
  local num="${1:-}"
  if [[ -z "$num" ]]; then
    read -r -e -p "Nummer des Images: " num
  fi

  if ! [[ "$num" =~ ^[0-9]+$ ]]; then
    echo "Ungueltige Nummer."
    return 1
  fi

  if (( num < 1 || num > ${#LAST_IDS[@]} )); then
    echo "Nummer $num ist ungueltig."
    return 1
  fi

  local id
  id="${LAST_IDS[$((num - 1))]}"

  docker image inspect "$id" --format \
    $'ID: {{.Id}}\nRepoTags: {{.RepoTags}}\nCreated: {{.Created}}\nSize: {{.Size}}\nArchitecture: {{.Architecture}}\nOS: {{.Os}}\nLabels: {{json .Config.Labels}}'

  echo
  echo "Containers:"
  local -a lines
  mapfile -t lines < <(docker ps -a --filter "ancestor=$id" --format '{{.ID}}|{{.Names}}|{{.Status}}')
  if [[ ${#lines[@]} -eq 0 ]]; then
    echo "- keine"
    return 0
  fi

  local line cid name status
  for line in "${lines[@]}"; do
    IFS='|' read -r cid name status <<< "$line"
    echo "- $name ($cid) - $status"
  done
}

purge_images() {
  local mode="$1"
  local force_yes="$2"

  case "$mode" in
    unused)
      list_unused_images
      if [[ ${#LAST_IDS[@]} -eq 0 ]]; then
        return 0
      fi
      ;;
    *)
      echo "Unbekannter Modus: $mode"
      return 1
      ;;
  esac

  if [[ ${#LAST_IDS[@]} -eq 0 ]]; then
    return 0
  fi

  if [[ "$force_yes" != "true" ]]; then
    if ! confirm_action "Alle aufgelisteten Images loeschen?"; then
      echo "Abgebrochen."
      return 0
    fi
  fi

  local -A seen=()
  local id
  for id in "${LAST_IDS[@]}"; do
    if [[ -n "${seen[$id]:-}" ]]; then
      continue
    fi
    seen[$id]=1
    remove_image_by_id "$id"
  done
}

print_help() {
  echo "Docker Image Manager"
  echo
  echo "Verwendung:"
  echo "  bash ./docker-image-manager.v1.sh [BEFEHL] [OPTIONS]"
  echo
  echo "Befehle:"
  echo "  list                  - Alle Docker Images auflisten"
  echo "  unused-images         - Images anzeigen, die von keinem Container genutzt werden"
  echo "  inspect               - Details zu einem Image anzeigen (inkl. Containerliste)"
  echo "  delete                - Einzelne Images nach Nummer loeschen"
  echo "  purge-unused          - Alle ungenutzten Images loeschen"
  echo "  help, -h, --help      - Diese Hilfe anzeigen"
  echo
  echo "Optionen:"
  echo "  --yes                 - Loeschen ohne Rueckfrage"
}

interactive_menu() {
  while true; do
    echo
    echo "Docker Image Manager"
    echo "1) Images anzeigen + Details"
    echo "2) Ungenutzte Images anzeigen"
    echo "3) Image loeschen (per Nummer)"
    echo "4) Alle ungenutzten Images loeschen"
    echo "0) Beenden"
    read -r -e -p "Auswahl: " choice

    case "$choice" in
      1)
        list_all_images
        if [[ ${#LAST_IDS[@]} -eq 0 ]]; then
          continue
        fi
        read -r -e -p "Nummer fuer Details (Enter fuer zurueck): " detail_num
        if [[ -n "$detail_num" ]]; then
          inspect_image_by_number "$detail_num"
        fi
        ;;
      2)
        list_unused_images
        ;;
      3)
        list_all_images
        if [[ ${#LAST_IDS[@]} -eq 0 ]]; then
          continue
        fi
        if ! select_images_by_numbers ""; then
          continue
        fi
        echo "Ausgewaehlte Images:"
        print_selected_images
        if confirm_action "Ausgewaehlte Images loeschen?"; then
          delete_selected_images
        else
          echo "Abgebrochen."
        fi
        ;;
      4)
        purge_images "unused" "false"
        ;;
      0)
        echo "Tschuess."
        exit 0
        ;;
      *)
        echo "Ungueltige Auswahl."
        ;;
    esac
  done
}

main() {
  require_docker

  local cmd=""
  local force_yes="false"
  local -a extra_args=()

  for arg in "$@"; do
    case "$arg" in
      --yes)
        force_yes="true"
        ;;
      -h|--help|help)
        cmd="help"
        ;;
      *)
        if [[ -z "$cmd" ]]; then
          cmd="$arg"
        else
          extra_args+=("$arg")
        fi
        ;;
    esac
  done

  if [[ -z "$cmd" ]]; then
    interactive_menu
    return 0
  fi

  case "$cmd" in
    list)
      list_all_images
      ;;
    unused-images)
      list_unused_images
      ;;
    inspect)
      list_all_images
      if [[ ${#LAST_IDS[@]} -eq 0 ]]; then
        return 0
      fi
      inspect_image_by_number "${extra_args[0]:-}"
      ;;
    delete)
      list_all_images
      if [[ ${#LAST_IDS[@]} -eq 0 ]]; then
        return 0
      fi
      if ! select_images_by_numbers "${extra_args[*]:-}"; then
        return 1
      fi
      echo "Ausgewaehlte Images:"
      print_selected_images
      if [[ "$force_yes" != "true" ]]; then
        if ! confirm_action "Ausgewaehlte Images loeschen?"; then
          echo "Abgebrochen."
          return 0
        fi
      fi
      delete_selected_images
      ;;
    purge-unused)
      purge_images "unused" "$force_yes"
      ;;
    help|*)
      print_help
      ;;
  esac
}

main "$@"